1. Field of the Invention
The present invention relates to technologies which assure data security of storage units connected by a network.
2. Description of the Related Art
In recent rears, technologies to boot a computer using a network boot method have being established. For instance, there are network boot methods which employ PXE (Preboot eXecution Environment), EtherBoot, and iBoot. However, in the methods, there are security problems since bootfiles are allowed to be shared. In other words, a computer may use a bootfile which the computer is not actually authorized to use, to execute a network boot. Furthermore, an unexpected computer may use a bootfile to execute a network boot and access information which the computer is not actually authorized to access.
Therefore, there has been disclosed a conventional method to switch storage units which are accessed by computers, using VLAN (Virtual LAN) technology (for instance, see US patent application publication No. US 2003/0101239 A1). VLAN technology is a technology to set virtual network segments. And, VLAN technology can logically change a network topology with being independent of a physical network topology of network devices. VLAN technology does not allow even devices which are connected to adjacent ports of a same network device, to communicate each other, when settings of network segments of the devices are different.
Such a switching method can prevent a storage unit from being accessed by a computer which actually has no access right to the storage unit. Consequently, it is possible to improve data security for the storage unit. In other words, it is possible to provide a secure IP protocol storage device.